Dispenser for an aerosol can

ABSTRACT

A dispenser to be fitted on the top of an aerosol can so as to atomize a very small quantity of the contents of the aerosol can at regular intervals automatically. An attachment having an electrically operated valve is secured to the aerosol can. Operation of the valve takes place via a controller which is supplied by power by a photovoltaic or solar panel. In this way, it is ensured that dispensing the desired material takes place only when there is sufficient light striking the solar panel.

FIELD OF THE INVENTION

The present invention relates to a dispenser according to the preambleof claim 1.

A dispenser of this type is generally known from the prior art. A devicethat is, for example, used in public toilets for periodic dispensing ofan air freshener. Aerosol cans of this type are also used in greenhousesand other locations where a dosage of, for example, a herbicide has tobe dispensed periodically.

BACKGROUND OF THE INVENTION

Motor-driven systems are generally used in the prior art, which systemsdepress the conventional spray head of the aerosol can. Saidmotor-driven systems, together with the further circuitry and theaerosol can, are housed in a casing. The batteries for supplying thepower for the control and drive of the motor are likewise located insaid casing. In some embodiments the aim is to make the life of thebatteries equal to the life of the aerosol can or to make the batterylife twice that of the aerosol can.

In U.S. Pat. No. 3,666,144 an attachment is described which is to beplaced between the atomiser nozzle of an aerosol can and the aerosol canitself. A coil-operated valve is contained in said attachment. With thisembodiment the life of the batteries can be extended appreciably becausecurrent consumption is appreciably limited.

In practice this type of simultaneous use of the aerosol can and thebatteries proves particularly difficult to realise. This means thateither the aerosol can is not emptied completely or that the battery isnot exhausted at the time the aerosol can is changed. Moreover, it isnecessary for maintenance staff to replace both the aerosol can and thebatteries.

Some embodiments have indicators to display the number of times aerosolhas been dispensed by the aerosol can or the residual power in thebattery. This counting is ineffective if the aerosol can contains agreater or lesser number of doses. One problem with the batteryindicator is that as soon as the battery is virtually empty no furtherindication can be given of the contents of the aerosol can or thecontents of the batteries themselves. That is to say, there is no clearindication for maintenance staff. A positive approach to this problem,that is to say allowing an indicator to remain permanently lit if thebattery is not yet empty, is found to consume a particularly highproportion of the battery charge and this approach is therefore also notdesirable.

A further problem is that, especially in public toilets, a separatecircuit is needed to prevent a dosage also being dispensed during thenight when the toilets are not in use. For this purpose it is necessaryto set the time or to use a day/night sensor, which is complex and thereason why, in practice, devices of this type continue to run day andnight, which leads to wastage of the both the contents of the aerosolcans and of the batteries.

OBJECT OF THE INVENTION

The aim of the present invention is to provide a dispenser which doesnot have the above disadvantages and operates only if the surroundingsin which said device is located are in use and with which it is possibleto give a direct indication of whether or not the device is inoperation. independently of other effects of the surroundings, even whenthe aerosol can is almost empty.

SUMMARY OF THE INVENTION

This aim is achieved with a dispenser using a photovoltaic or solarcell.

Although the use of a photovoltaic or solar cell has been suggestedbefore, a photovoltaic cell of this type has always been used incombination with an accumulator or other rechargeable battery having arelatively large capacity. This meant that such a solar cell servedmerely to keep the battery charged at the required level. A constructionof this type is described, for example, in Netherlands PatentApplication 8102234 in the name of the Applicant.

The disadvantage of this construction was that a particularly largesurface area of solar cell was needed to operate the electric motor forthe fan which was used with this arrangement. Moreover, it is not simpleto make a differentiation between when the device is and is not in use,whilst, finally, there is no indication whatsoever as to whether a lightlevel adequate for the solar cell is available. After all theaccumulator used will be fully charged when it is installed. It willbecome clear only after some time that the accumulator used isdischarging more energy to the motor than is being charged by the solarcell. At that point in time the installers are no longer on site.

With the device according to the invention a relatively small solar cellcan suffice as a result of the use of the attachment having the valvemounted therein. The effect of the direct power supply from thephotovoltaic cell and the accumulator, such as a capacitor, having arelatively small capacity to the valve is that no substantial dispensingtakes place when, for example, the toilets are not in use, that is tosay when the lights are off in the case of public toilets. Furthermore,the installers can establish immediately at the time of installationwhether or not there is adequate light by checking whether atomisationstarts at the desired point in time.

The various features can be further optimised in that the controller isprovided with an indicator showing the light intensity. That is to saythat, for example, a light emitting diode or the like which isilluminated when there is adequate light is located on the casing of thedispenser. The optimum positioning of the casing and, more particularly,of the solar cell mounted thereon, can then be taken into accountimmediately at the time of installation.

Furthermore, sensor means to sense the condition of charge of theaerosol can can be present, which means are connected to the controlleraccording to the invention. As a result, a light signal, for example,can be given if the charge level falls below a certain level, which, forexample, corresponds to the empty state of the aerosol can. Because thelowering of the contents of the can does not proceed in parallel withthe energy emitted by the solar cells, it can, in contrast to the casewith constructions which have batteries which become exhausted, beassumed with reasonable certainty that if the indicator is out there areno problems, whilst problems are to be expected when the indicator comeson.

These sensing mean can comprise several embodiments.

First of all it is possible to provide a pressure sensor which could berealised as a switch or other pressure sensitive element introduced inthe aerosol can which will give a signal if the pressure in the aerosolcan drops.

It is also possible to provide a gas sensitive switch near the outflowopening of the dispenser. If no gas or liquid from the aerosol can issensed whilst the dispensing device is activated it can be concludedthat the aerosol can is empty.

It is also possible to provide some kind of flap which is blown away bythe discharging gas. Movement of this flap can be sensed. A furtherpossiblity is to provide a tube inside a coil which coil is connectedwith the aerosol can. In this tube a metal part is provided which willmove because of the pressure of the aerosol can and will result in achange of induction of the coil.

However, preferably in the outflow opening a temperature sensitivedevice such as a resistance is provided. If the aerosol can isactivitated evaporated gas possibly comprising some evaporating liquiddroplets move along the resistance resulting in its cooling. This gas isevaporated in prior art aerosol cans in the area of the outflow tubeextending from the top of the aerosol can to its bottom.

However, if the aerosol can is nearly empty the gas will alreadyevaporate in the can itself. In that case the gas will have aconsiderably higher temperature than in the condition wherein the gas isonly (partially) evaporated in the tube extending into the can to thedispensing opening.

It will be clear that such a sensing device cannot only be used in thedispenser according to the invention but in combination with any otherprior art aerosol can in which it is necessary to have indicationwhether or not it is still filled.

Any device to be provided outside from the aerosol can has the advantagethat it has not to be changed together with the aerosol can if this canis empty.

According to an advantageous embodiment of the invention, positionsensor means are fitted close to the part coming into contact with thetop of the aerosol can in order to ensure that there is a completeconnection between the aerosol can and the attachment.

To prevent incorrect aerosol cans being used in combination with theattachment described above, coupling means which engage with one anothercan be fitted on both the attachment and the aerosol can.

As indicated above, the aerosol can can spray any agent which has to bedispensed periodically, such as air fresheners and herbicides.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail below with reference toan illustrative embodiment shown in the drawing. In the drawing:

FIG. 1 shows a perspective front view of the exterior of the deviceaccording to the invention;

FIG. 3 shows an exploded view of the device according to the invention;

FIG. 2 shows a detail side view of the aerosol can in combination withthe attachment according to the invention; and

FIG. 4 shows the circuit diagram for the electrical connections andcontrol of the various components.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1, the holder for accommodating an aerosol can is indicated inits entirety by 1. A solar panel 2 is fitted on the front of saidholder. There is also a dispensing orifice 3 for the medium to be dosed,and LED indicators 11, 12 are located on the lower side.

FIG. 2 shows a side view of the holder. It can be seen that the holdercomprises a retainer 13 for an aerosol can, as well as diverse snap-shutmeans, which are not shown in more detail, for fixing to a base plate,which initially is fixed to the wall shown in FIG. 1. Constructions ofthis type are generally known from the prior art. Accumulator 30 isconnected to controller 25 which is not shown in this figure.

Retainer 13 is suitable for accommodating an aerosol can, only the upperpart of which is shown in FIG. 3. The top 6 is designed to interact withan attachment 5, which is to be fixed thereto. This attachment 5 isshown in the exploded diagram in FIG. 3. It comprises, from bottom totop, an attachment/aerosol can coupling 14 and a valve housing 15, inwhich a coil housing 16 is accommodated. An electrically controllablecoil 7, provided with lead 17, fits in coil housing 16. A propellant gascoupling 18 and a piston holder 19 are fitted inside coil 7. A valve 8,comprising a spring 20, piston 21, rubber seal 22 and piston housing 23,fits in the piston holder. A metal ring to intensify the magnetic fieldabuts piston housing 23. An O-ring 24 and pressure membrane 27 completethe valve device. A valve cover 28 interacts with the valve housing 15.On top of said valve cover 28 there is a dispensing nozzle 9 of the typegenerally known from the prior art. A temperature sensor 10 such as aNTC or PTC resistance can be fitted to be contacted with the gas flowfrom the aerosol can. This temperature sensor 10 is connected via lead29 to the controller, which is not shown in more detail.

The electrical connections of various components are showndiagrammatically in FIG. 4. The coil 7 of the valve is connected vialead 17 to controller 25. The same applies in the case of temperaturesensor 10, which is connected to the controller 25 via lead 29.Controller 25 is likewise electrically connected to a timer device 26and to the photocell 2. LED indicators 11 and 12 are also connected tothe controller 25. An accumulator such as a capacitor 30 is provided.

The device described above functions as follows:

The installer will take account of LED indicator 11 when positioning theholder, containing aerosol can and other components fitted therein, inthe lighted area concerned. When connected with controller 25 andphotocell 2, said LED indicator 11 is so designed that a signal is givenif sufficient energy is generated by the photovoltaic cell 2. The chargecondition of accumulator 30 is not taken into account. Duringinstallation, the installer can immediately check whether there isadequate light to guarantee subsequent operation. It is, of course, alsopossible to dispense with said indicator and to use a light meter tocarry out the various checks.

The device according to the invention is ready for use immediately afterinstallation. Operation of the device is controlled by electricity fromthe photovoltaic cell 2. The timer circuit 26 is actuated by this means.Depending on the time which has been preset or is to be set afterinstallation, said timer circuit 26 sends a pulse, the length of whichcan likewise be set for, for example, a few tens of milliseconds, tocontroller 25. In response to said pulse, energy originating from bothphotovoltaic cell 2 and accumulator 30 is transmitted to the coil 7 ofvalve 8. By this means valve 8 is actuated so that a small quantity ofgas escapes from aerosol can 4. Valve 8 functions in the same way as theconstruction described in U.S. Pat. No. 3,666,144.

If the area concerned is not in use, that is to say the light isswitched off or it is nighttime, energy will no longer be produced bythe photovoltaic cell. This means that the controller 25 will functionas long as sufficient charge is provided in accumulator 30. This isdesigned for about two dispensing operations. After that controller 25is no longer functioning and, therefore, even if the timer device 26were to emit a further signal this would have no effect on the operationof the coil 7 of valve 8.

The temperature sensor 10 measures the temperature of the outflowing gasfrom the aerosol can. If this temperature rises below a preset `toohigh` value, such as the temperature when the can is empty, the hightemperature signal is processed by controller 25 such that LED indicator12 gives a signal. Consequently an indication that the aerosol can 4 hasto be changed is available for maintenance staff.

This is based on the idea that in the aerosol a tube extends from thebottom to the nozzle through which the product to be dispensed isexpelled because of propulsing gas, such as propane or butene.Evaporation of the liquid propulsing gas occurs either in this tube ornear the discharge opening of either the aerosol can or the dispensingdevice. Anyway the temperature of the gas giving the dispensing devicewill drop in temperature which is sensed by sensor 10.

However, if the aerosol can becomes empty the last part of the gas willevaporate in the can itself resulting in a lower temperature drop of thegas at the discharge opening of the dispenser which will be sensed bysenor 10. It has to be understood that such a sensing device can be usedin combination with any other dispensing device known in the prior art.A temperature drop in the filled condition of the aerosol can of about20° C. has been observed which is easy to sense.

Although the invention has been described above with reference to apreferred embodiment, it must be understood that numerous modificationscan be made thereto without going beyond the scope of the presentApplication. For instance, it is possible to construct the valve/aerosolcan coupling in such a way that, for example, an electrical connectionis produced when the coupling is fitted correctly and a circuit isbroken if said fitting is incorrect. In this way it is guaranteed that adose is dispensed only when the fitting is correct. Moreover, the top ofthe aerosol can can be modified to make it possible to combine onlyspecific types of aerosol cans with the attachment 5 according to theinvention. Furthermore, the LED indicators can be replaced by audioindicators.

I claim:
 1. In a dispenser for use with an aerosol can, comprising anattachment adapted to be placed on the top of an aerosol can, thatattachment having a valve operated by a coil for dispensing contents ofa said aerosol can, a controller connected to the coil to controlmovement of the valve, a timer circuit for the controller and a powersupply for powering the coil; the improvement wherein the power supplycomprises photovoltaic means for receiving ambient light and convertingsaid ambient light into electric power, accumulator means connected tothe photovoltaic means for accumulating said electric power andconnected to said controller to supply the accumulated electric powerfrom said accumulator means to said controller; said controller beingarranged and constructed to power the coil only when there has beensufficient ambient light to charge said accumulator means from saidphotovoltaic means.
 2. A dispenser as claimed in claim 1, wherein in thecontroller has an indicator indicating light and ambient lightintensity.
 3. A dispenser as claimed in claim 1, and temperature sensormeans connected to the controller such that when the temperature of gasflowing from the aerosol can rises too high, the temperature sensingmeans causes the controller to give a signal that the aerosol can is tobe changed.
 4. A dispenser as claimed in claim 1, and a pressure sensormeans connected to the controller to cause the controller to give anindication when the pressure of the outflowing gas from the aerosol canfalls too low and falls below a predetermined minimum.